Poly(3-hydroxyalkanoates) (PHAs) are biodegradable plastics and carbon storage materials that are synthesized by a myriad of microorganisms. PHAs are divided into groups based on repeating unit size. PHAs with repeating units of three to five carbons in length are short-chain-length (SCL) PHAs, and PHAs with repeating units of six to fourteen carbons in length are medium-chain-length (MCL) PHAs. Differences in repeating unit composition influence the physical properties of PHAs. SCL PHA homopolymers such as poly-3-hydroxybutyrate (PHB) have been previously produced, but methods to control the repeating unit composition of the MCL PHAs have been limited. Previous attempts to control MCL PHA synthesis in native and recombinant PHA-producing organisms have resulted in narrow ranges of repeating unit control. Typically, control is limited to only a couple of repeating units within one organism or control is lost once the number of carbons in the repeating unit exceeds seven
Thus, the composition of medium-chain-length (MCL) poly(3-hydroxyalkanoate) (PHA) biopolymers is normally an uncontrollable random mixture of repeating units with differing side chain lengths. Attempts to generate MCL PHA homopolymers and gain control of the repeating unit composition have been reported for native or natural PHA-producing organisms but have limited ranges for the different sizes of repeating units that can be synthesized.
Citation or identification of any reference in Section 2, or in any other section of this application, shall not be considered an admission that such reference is available as prior art to the present invention.